GPIO: Add driver for 74xx-ICs with MMIO access
This patch adds driver to support GPIO functionality for 74xx-compatible
ICs with MMIO access. Compatible models include:
1 bit: 741G125 (Input), 741G74 (Output)
2 bits: 742G125 (Input), 7474 (Output)
4 bits: 74125 (Input), 74175 (Output)
6 bits: 74365 (Input), 74174 (Output)
8 bits: 74244 (Input), 74273 (Output)
16 bits: 741624 (Input), 7416374 (Output)
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-74xx-mmio.c b/drivers/gpio/gpio-74xx-mmio.c
new file mode 100644
index 0000000..0763655
--- /dev/null
+++ b/drivers/gpio/gpio-74xx-mmio.c
@@ -0,0 +1,170 @@
+/*
+ * 74xx MMIO GPIO driver
+ *
+ * Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/basic_mmio_gpio.h>
+#include <linux/platform_device.h>
+
+#define MMIO_74XX_DIR_IN (0 << 8)
+#define MMIO_74XX_DIR_OUT (1 << 8)
+#define MMIO_74XX_BIT_CNT(x) ((x) & 0xff)
+
+struct mmio_74xx_gpio_priv {
+ struct bgpio_chip bgc;
+ unsigned flags;
+};
+
+static const struct of_device_id mmio_74xx_gpio_ids[] = {
+ {
+ .compatible = "ti,741g125",
+ .data = (const void *)(MMIO_74XX_DIR_IN | 1),
+ },
+ {
+ .compatible = "ti,742g125",
+ .data = (const void *)(MMIO_74XX_DIR_IN | 2),
+ },
+ {
+ .compatible = "ti,74125",
+ .data = (const void *)(MMIO_74XX_DIR_IN | 4),
+ },
+ {
+ .compatible = "ti,74365",
+ .data = (const void *)(MMIO_74XX_DIR_IN | 6),
+ },
+ {
+ .compatible = "ti,74244",
+ .data = (const void *)(MMIO_74XX_DIR_IN | 8),
+ },
+ {
+ .compatible = "ti,741624",
+ .data = (const void *)(MMIO_74XX_DIR_IN | 16),
+ },
+ {
+ .compatible = "ti,741g74",
+ .data = (const void *)(MMIO_74XX_DIR_OUT | 1),
+ },
+ {
+ .compatible = "ti,7474",
+ .data = (const void *)(MMIO_74XX_DIR_OUT | 2),
+ },
+ {
+ .compatible = "ti,74175",
+ .data = (const void *)(MMIO_74XX_DIR_OUT | 4),
+ },
+ {
+ .compatible = "ti,74174",
+ .data = (const void *)(MMIO_74XX_DIR_OUT | 6),
+ },
+ {
+ .compatible = "ti,74273",
+ .data = (const void *)(MMIO_74XX_DIR_OUT | 8),
+ },
+ {
+ .compatible = "ti,7416374",
+ .data = (const void *)(MMIO_74XX_DIR_OUT | 16),
+ },
+ { }
+};
+MODULE_DEVICE_TABLE(of, mmio_74xx_gpio_ids);
+
+static inline struct mmio_74xx_gpio_priv *to_74xx_gpio(struct gpio_chip *gc)
+{
+ struct bgpio_chip *bgc = to_bgpio_chip(gc);
+
+ return container_of(bgc, struct mmio_74xx_gpio_priv, bgc);
+}
+
+static int mmio_74xx_get_direction(struct gpio_chip *gc, unsigned offset)
+{
+ struct mmio_74xx_gpio_priv *priv = to_74xx_gpio(gc);
+
+ return (priv->flags & MMIO_74XX_DIR_OUT) ? GPIOF_DIR_OUT : GPIOF_DIR_IN;
+}
+
+static int mmio_74xx_dir_in(struct gpio_chip *gc, unsigned int gpio)
+{
+ struct mmio_74xx_gpio_priv *priv = to_74xx_gpio(gc);
+
+ return (priv->flags & MMIO_74XX_DIR_OUT) ? -ENOTSUPP : 0;
+}
+
+static int mmio_74xx_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+ struct mmio_74xx_gpio_priv *priv = to_74xx_gpio(gc);
+
+ if (priv->flags & MMIO_74XX_DIR_OUT) {
+ gc->set(gc, gpio, val);
+ return 0;
+ }
+
+ return -ENOTSUPP;
+}
+
+static int mmio_74xx_gpio_probe(struct platform_device *pdev)
+{
+ const struct of_device_id *of_id =
+ of_match_device(mmio_74xx_gpio_ids, &pdev->dev);
+ struct mmio_74xx_gpio_priv *priv;
+ struct resource *res;
+ void __iomem *dat;
+ int err;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ dat = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(dat))
+ return PTR_ERR(dat);
+
+ priv->flags = (unsigned)of_id->data;
+
+ err = bgpio_init(&priv->bgc, &pdev->dev,
+ DIV_ROUND_UP(MMIO_74XX_BIT_CNT(priv->flags), 8),
+ dat, NULL, NULL, NULL, NULL, 0);
+ if (err)
+ return err;
+
+ priv->bgc.gc.direction_input = mmio_74xx_dir_in;
+ priv->bgc.gc.direction_output = mmio_74xx_dir_out;
+ priv->bgc.gc.get_direction = mmio_74xx_get_direction;
+ priv->bgc.gc.ngpio = MMIO_74XX_BIT_CNT(priv->flags);
+ priv->bgc.gc.owner = THIS_MODULE;
+
+ platform_set_drvdata(pdev, priv);
+
+ return gpiochip_add(&priv->bgc.gc);
+}
+
+static int mmio_74xx_gpio_remove(struct platform_device *pdev)
+{
+ struct mmio_74xx_gpio_priv *priv = platform_get_drvdata(pdev);
+
+ return bgpio_remove(&priv->bgc);
+}
+
+static struct platform_driver mmio_74xx_gpio_driver = {
+ .driver = {
+ .name = "74xx-mmio-gpio",
+ .of_match_table = mmio_74xx_gpio_ids,
+ },
+ .probe = mmio_74xx_gpio_probe,
+ .remove = mmio_74xx_gpio_remove,
+};
+module_platform_driver(mmio_74xx_gpio_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
+MODULE_DESCRIPTION("74xx MMIO GPIO driver");